Process of making ion-exchanging preparations and product thereof



Patented Oct. 28, 1941 PROCESS OF MAKING ION-CHANGING PREPARATIONS OF AND PRODUCT THERE- Paul C. Goetx, Mount Holly, N. 1., assignor to The Permutit Company, New York, N. Y., a corporation of Delaware No Drawing.

Application November 20, 1937,

Serial No. 175,733

9 Claims.

This invention relates to processes of making ion-exchanging preparations; and it comprises a method of making ion-exchanging preparations from carbonizable or carbonaceous materials such as coal and lignlte, wherein the carbonaceous material is treated with a strong oxidizing acid such as sulfuric acid or anhydride, in conjunction with an oxidizing agent or oxidation accelerant or both, thereby securing a preparation of high exchange and cation extracting power; all as more fully hereinafter set forth and as claimed.

There have recently been developed granular carbonaceous preparations of hard rigidnature adapted for treating flows of water, characterized by being insoluble in water and dilute reagents, and by having zeolitic characteristics, That is, upon treatment of the preparations with acid or salt, they can be put in condition for removing cations from water, and can be regenerated when exhausted, by a repetition of the treatment. Upon flowing hard or soft water past the gran ules, the basic metallic ions (e. g. calcium or sodium) or cations are taken up by the granules. releasing hydrogen or another cation to the water. In due course, the granules become fully charged with calcium, magnesium and/or sodium from the water. Their activity can be restored by a new treatment with acid or with a saline solution, as the case may be. These preparations are particularly useful with acid regeneration; as hvdrogen ion exchange materials for cation extraction. Since the cation in the water being treated are in combination with acidic ions, the acid is set free by the exchange, and if the acid is carbonic acid, HzCOs. it can be removed from the water by heating or aeration, thereby yielding a water of minimized content of dissolved matter.

A wide range of carbonaceous raw materials is available for preparation of these ion exchange materia s. Certain lignites and bituminous coals give particularly good results. The best preparational processes usually involve subjectlng granulated raw material to the action of sulfuric acid, or of a substituted sulfuric acid, or of sulfuric anhydride (80:). Excellent materials for the t eatment of flowing water can be made by submitting coal and lignite to the action of sulfuric acid or S03. Fuming sulfuricacid may be used. Hard durable granules can be made having a high exchange power when used in the ordinary softening methods with brine regeneration and capable of use as hydrogen zeolites.

humic matter of coal is complex and little understood. There is sulfonation of aromatic constituents and esteriflcation of unsaturated groups with production of half esters of sulfuric acid. Whatever the chemical action, there is production of wholly insoluble materials which, as stated, have ion exchange and cation extracting properties. In addition to the two chemical actlons mentioned which may be grouped as sulfatlng, there are other actions and one is oxidation, with corresponding reduction of some portion of the acid to 802 and other reduction products of sulfuric acid.

I have discovered that the oxidizing action of the sulfuric acid is a desirable one, contrary to what might be expected; and that better products can be made by supplementing or enhancing the oxidizing action of the sulfuric acid. I sometimes employ an oxidizing agent, such as nitric acid, capable of exerting an oxidizing action independent of the action of the sulfuric acid: the oxidizing agent being used in admixture with the suifating acid or in a separate step. Sometimes I use a substance capable of catalyzing the oxidizing action of H1504; e. g. alum (aluminum sulfate) and sometimes I use substances having both effects, for example potassium permanganate, which is an oxidizing agent per se and which in the presence of sulfuric acid forms manganese sulfate which catalyzes the oxidizing action of the sulfuric acid. The oxidizlng agents, when such are used, tend to preclude loss of 80: as 80:, which is advantageous. Almost any convenient oxidizing agent may be used; ferric salts, manganese dioxide, nitrates and nitric acid, perchlorates, chromates, hydrogen peroxide, permanganates, arsenates', arsenic acid, etc. etc. Operating under the present invention, the final product has an enhanced exchange power; that is, the amount of cations it can extract from water between regenerations is materially increased. In many cases substances prepared according to the invention have exchange powers 20 to 40 per cent or more greater than corresponding materials prepared without the aid of an oxidizing agent.

Using oxidizing agents, these can be used in admixture with the sulfuric acid during attack on the coal, or in some cases can be applied subsequently to the acid treatment, or the carbonaceous material can be treated with the oxidizing agent prior to the acid treatment. Other oxidatlon promoting agents are best employed in admixture with the acid, or as a preliminary treat- The action of sulfuric acid or B0: on the ment.

The following meciflc examples illustrate the process applied to a certain lignite, which is especially well adapted for making zeolltic preparations.

1. A cubic foot of Volvo lignite, of average granule size 16 to 40 mesh, was treated with a mixture of 1.25 pounds M1102 and 115 pounds of 93 per cent strength sulfuric acid, for a period of 6 hours at a temperature of 150 C. The liquor was then drained oil and the granules were washed and dried. A cubic foot or the preparation was treated with flowing hard water until exhausted, and was then regenerated with 8 pounds NaCl in the form of a per cent solution. The exchange power was over 10,000 grains per cubic foot (expressed as CaCOa) and the material retained this high value through subsequent regenerations.

In this example the manganese sulfate formed tended to catalyze the oxidizing effect of the H2804.

Treatment 01 the raw lignite with said admixed with KMnOc, under similar conditions likewise yielded highcgrade preparations. Using such powerful oxidants as KMnOr plus H2804, the temperatures. etc., should be adjusted so as to prevent spontaneous ignition of the lignl from taking place.

2. A cubic foot 01' Velva lignite granulated to 16-40 mesh (that is, of such size that all granules pass ll. screen with -16 meshes to the inch but all are retained on a. acre'eil havlng 40 meshes to the inch) was mixed with? pounds of ferric chloride (monomer lived in 1.5 gallons of water, and then dried ,at about 110 0., without washing. The dried lignite was then intimately mixed with 115 pounds of 66 B. H2304 (93 per cent E2804) and the mixture oi acid and lignite allowed to stand 12 hours at room temperature. The lignlte was put in a lead-dined tank. the liquor drained off, and the excess free acid washed out by allowing water to percolate slowly through the mass of lignite.

The washed product was ready for use as an ion exchanging material and could be regenerated with either a metal salt as, for example, sodium chloride, or an acid, e. g. dilute I-ICl. Thus it can be used in either the sodium or hydrogen cycles tor removing cations from water.

The exchange capacity of the product was about 8,000 grains hardness or cation removal (expressed as calcium carbonate) per cubic foot oi treated lignite.

The ferric chloride in this example may be replaced by other iron, nickel, cobalt, chromium or manganese salts of oxidizing character and similar results will be obtained. For example, the lignite can be treated with NiSOJHaO or MnSOaGI-IzO and dried, then treated with acid: the nickel or manganes salts in such case serving as oxidation promoting agents for the subsequently applied 11:804.

3. A cubic foot of the same granulated Velva lignite was mixed with 115 pounds o! 66' B6. H280; to which was added 1.25 pounds of commereial alum (aluminum sulfate). The mixture was allowed to stand and react ior about 12 hours and then heated to dryness at a temperature not exceeding 150 C. The dried treated liBnite was washed in a lead-lined tank to remove the excess free acid.

Th washed product, with or without a preliminary drying at 100 0.. was ready for use as an ion exc ang material as in the case of the product of Example 1. The ion exchange capacity of H1O is probably formed in the actions.

the product was about 8.000 grains r cubic foot, regenerating with either a metal s t or an acid. using a 100 per cent excess of the regenerating substance beyond the theoretical amount.

The alum in this example served to accelerate the oxidizing effects of the H2804. V

4. A suitabl lignite in granular form. was treated with a mixture of concentrated H2804 and concentrated HNO: (06 per cent strength) in volume ratio 17:2, and the treated material washed and dried. It had an exchange power 60 per cent higher than corresponding material prepared without the addition of I-INOs. Chromic acid can be substituted for nitric in this example to achieve similar results.

In the examples given, the lignite was treated with substantially anhydrous reagents. Some Use of such salts as aluminum chloride in anhydrous form allows their water-binding capacity to be utilized to the full. However, sometimes it is desirable to apply the invention to processes wherein the coal etc. is treated with a dilute acid, and water is gradually evaporated of! to concentrate the acid (the invention or another). My invention is equally well applicable to such procedures. The final products are improved.

Sulfuric anhydrlde (a) in conjunction with a suitable oxidizing agent can be used in lieu of sulfuric acid. The S0: is conveniently supplied as hot vapors from the catalytic oxidation of S0: with air; the vapors containing diluent nitrogen from the air. Phosphoric anhydride can be used in lieu of sulfuric acid, advantageously at high temperatures. Moreover acids such as chlorsulionic acid can be employed in conjunction with oxidizing agents to achieve similar results. With some oi my products the exchange capacity can be enhanced still further by sub- ,iecting the acid-treated carbonaceous material to heat in the presence of the oxidizing agent, prior to the final washing.

The oxidizing salts of chromium, manganese, cobalt, nickel and iron can be regarded as oxygen accelerants as well as oxidizing agents per se and I sometimes use them in conJunction with other simple oxidizing agents such as HNOa, to function as accelerants as well as oxidizers.

While certain bituminous and anthracite coals, llgnites, and coke and semi-coke are especially satisfactory. my process can also be applied with advantage to other carbonaceous or carbonlzable raw materials, including the following: wood, charcoal, peat, cork, pitch, tar, sugar, dextrine, certain organic acids and their salts. rats and fatty acids, thickened sulfite waste liquor, soaps; and mixtures 01 these materials. The carbonaceous materials can be combined with inactive carrier bodies, such as burnt clay granules etc., before, during or alter the acid treatment.

What I claim is:

1. In the manufacture of a carbonaceous ion exchange material, the step of subjecting a carbonaceous material 01 the class consisting of anthracite coal, bituminous coal, lignites, coke, wood, charcoal, peat, cork, pitch, and thickened sulilte waste liquor to the simultaneous action of a strong sultating agent and a relatively small proportion of at least one oxidation promoting agent selected from the class consisting of alum, hydrogen peroxide; perchlorates, arsenates, arsenic acid, manganese dioxide, chromic acid, and the oxidizing salts of chromium. manganese, cobalt, nickel and iron, for. a sufllcient length 01 time to sulfate and materially improve the ionexchange value of the carbonaceous material.

2. A method as defined in claim 1 in which the carbonaceous material is treated with a mixture of the suliating and oxidation promoting agents.

8. A method as defined in claim 1 in which the carbonaceous material is treated with an oxidation promoting agent prior to the treatment thereof with the sulfating agent.

4. The method of claim 1 wherein the carbonaceous starting material is a lignite.

5. The method 0! claim 1 wherein the carbonaceous starting material is bituminous coal.

6. The method of claim 1 wherein the carbonaceous starting material is charcoal.

I. A solid, water insoluble granular ion-exchanging carbonaceous product prepared for the treatment of water containing dissolved salts by subjecting a carbonaceous material of the class consisting of anthracite coal, bituminous coal, lignites, coke, wood, charcoal, peat, cork. pitch and thickened suliite waste liquor to a sultating treatment by the simultaneous action of a straw sultating agent and a relatively small proportion oi an oxidation promoting agent selected from the class consisting of alum, hydrogen peroxide, perchlorates, arsenates, arsenic acid, manganese dioxide, chromic acid, and the oxidizing salts of chromium, manganese, cobalt, nickel and iron.

8. A granular carbonaceous ion exchange material for treating water containing dissolved salts to reduce the total solids content thereof comprising a water insoluble carbonaceous solid prepared by subjecting coal to a suliating treatment by the simultaneous action oi a strong sulfating agent and a relatively small proportion of an oxidation promoting agent selected from the class consisting of alum, hydrogen peroxide. perchlorates, arsenates, arsenic acid, manganese dioxide, chromlc acid, and the oxidizing salts of chromium, manganese, cobalt, nickel and iron.

9. A granular carbonaceous ion exchange material for treating water containing dissolved salts to reduce the total solids content thereof comprising a water insoluble solid prepared by sub- Jecting llgnite to a sultating' treatment by the simultaneous action of a strong suiiating agent and a relatively small proportion of an oxidation promoting agent selected from the class consisting of alum, hydrogen peroxide. perchlorates, arsenates, arsenic acid, manganese dioxide, chromic acid, and the oxidizing salts of chromium, manganese, cobalt, nickel and iron.

PAUL C. GOETZ. 

